1. Field of the Invention
The invention concerns a flow-controlled wind rotor adjustable by a wind vane and having a vertical axis of rotation and rotating blades revolving around the axis.
2. Background
Wind rotors with vertical rotation axes are known in the art as Savonius rotors, Darrieux rotors, vertical dual rotors, or Jackson rotors. Jackson rotors have not only a vertical axis, but comprise also blade-like plates, revolving around the vertical axis and simultaneously turning around their own axis by 180°.
Based on the design of Jackson rotors, solutions have been developed and described, e.g., in specifications of German Patents DE 198 47 469 A, DE 81 119 10 U1 and DE 39 18 184A1.
The invention disclosed in DE 30 18 211 C2 has a design similar to that of a Darrieux rotor. This rotor includes, however, blades having only a limited movement. The efficiency of Darrieux rotors is low. They require strong winds and frequently an auxiliary starter.
Wind motors most commonly-used in practice employ rotors having a horizontal axis of rotation and propeller-like blades rotating around that axis.
Rotor blades working based on this principle are much flatter at the outside than near the axis of rotation. They use as little as 16 to 27% of the theoretically-available wind energy. A support tower for wind rotors which revolve around a horizontal axis must be higher than for rotors revolving around a vertical axis of rotation. The blades working like a propeller move unevenly to the wind flow along their entire length. They are slower near the axis than at the edges of the blades. This results in considerable noise and a poor use of the working area of the blade.
In the specification DD 232 959 A1 described is a rotor for wind motors having a vertical axis, wherein an unsymmetrical design has been used allowing for automatic or forced adjustments of the angles of attack at any time during operation so that the aerodynamic forces constantly change to keep the direction of rotation invariant. With the increase of wind power and the change of the angles of attack of the rotor blades, the number of revolutions will decrease, and aerodynamic forces will drop to around zero. The blades of this wind motor are on one hand fixedly interconnected by means of gears and timing belts, on the other hand, however, are freely movable to allow them to adjust, with their special aerodynamic profile, automatically and optimally to the direction of the wind. Still, it is not discernable how the basic orientation of the rotor blades can change to follow the direction of the wind so as to enable the wind motor to start automatically.